Three men are being questioned in connection with the murder of a banker set upon after confronting a gang attacking a homeless man.
Father-of-two Frank McGarahan, 45, of Much Hadham, Herts, died in hospital on Monday after being injured in central Norwich in the early hours of Sunday.
Police said on Tuesday night that three men - all in their early 20s and from the Norwich area - had been arrested. They are being held at police stations across Norfolk.
Mr McGarahan was chief operating officer of Barclays Wealth, a section of Barclays Bank which manages the assets of some of the world's richest people, and had been enjoying a night out in Norwich before a family christening.
Police said he intervened when he saw thugs attacking a homeless Lithuanian man and his girlfriend. He was hurt after an "exchange of words" with the couple's attackers, said Detective Superintendent Chris Hobley.
Mr Hobley said Mr McGarahan, who had been for a meal and visited several bars, was at a taxi rank with his brother Kevin, who lives in Norwich, and a cousin when the incident happened.
A doorman working at a nearby strip club went to the group's aid when he heard sounds of a disturbance.
Darryl Lawton told the Mail newspaper that a gang of 12 thugs were, "really laying into" the 45-year-old. He said: "If I had been there just a few seconds earlier I could have saved Frank.
"They kicked me and punched me in the head and back. I took as much as I could, but I had to let go of the guy I was holding. When I turned around I could see that Frank was dead," he told the newspaper.
Police said Mr McGarahan was hurt at around 3am on Sunday and died in hospital yesterday without regaining consciousness. Mr Lawton suffered a broken jaw and Mr McGarahan's cousin also needed hospital treatment.
